Sepsis and septic shock represent the most common causes of death in ICU patients. Lung injury and the adult respiratory distress syndrome play a major contributor role in the mortality associated with sepsis. Endogenous cytokine production may contribute to such injury. The development of therapies directed toward the prevention of sepsis induced lung injury will require a clear understanding of the pathophysiology of such injury. In order to better define the pathophysiology of sepsis induced lung injury, in order to define the role cytokines might play in such injury measurements of pulmonary gas exchange and serial bronchoalveolar lavage were performed and peripheral blood samples were taken for cytokine assays, in a chronically tracheotomized canine model of human bacterial sepsis. Purpose-bred beagles were instrumented under local anesthesia with femoral and pulmonary arterial lines. Measurements of pulmonary gas exchange and pulmonary hemodynamics, as well as bronchoalveolar lavage were performed seven days before, during and ten days following an episode of surgically induced bacterial peritonitis in addition to cardiopulmonary studies, animals also had sequential blood samples drawn every hour for the first 12 hours and once every 24 hours for up to 10 days after the induction sepsis for cytokine analysis. Data for this study is still being obtained.